grondahl



Feb 3, 1931.- J. K. GRNDAHL 1,790,985

ELECTRICAL SIGNALING SYSTEM original Filed July 5o, 19g@ 4 sheets-sheet 1 ATTORNEYS Feb. 3, 1931. J. K. GRONDAHL ELECTRICAL SIGNALING SYSTEM 4 Sheets-Sheet 2 Original Filed July 30, 1926 INVENTOR JK. G/"Oadcr/Z ATTORNEYS Feb. 3, 1931.l

Jl K. GRONDAHL ELECTRICAL SIGNALING SYSTEM Original Filed July 30, 1926 4 Sheets-Sheet 3 .MUM

RSTUVWXYZ ATTORNEYS ABcoEFGx-IIJKLMNOP WITNESSES Feb. 3, 1931. J, K, GRONDAHL 1,790,985

ELECTRICAL SIGNALING SYSTEM Original Filed July 30, 1926 4 Sheets-Sheet 4 ,7:9 c JJ( @Poyuz'ol O D, -BY

(y0\ E Y 0 ATTORNEYS Patented Feb. 3, 1931 PATENT .OFFICE JEN S K. GROND'AHL, OF RED WING, MINNESOTA ELECTRICAL SIGNALING SYSTEM Application filed July 30, 1926, Serial N'o. 126,057. Renewed August 9, 1930.

This invention relates to improvements in electrical signaling systems, an object being to provide an apparatus for readily communicating intelligence to blind, near-blind and partially deaf ersons.

Other objects and advantages appear in the following specification, reference being had to the accompanying drawings, in which Figure 1 is an end elevation'of the translating machine. i

Figure 2 is a vertical cross section thereof.

Figure 3 is a plan View of the translating machine.

Figure 4 is a detail section of one of the plungers, taken on line 4-4 of rixrure 3,

Figure 5 is a detail view of known mechanism for turning the platen,

Figure 6 is a detail View of the carriage l escapement, 2o

space-bar mechanism, U

r igure 8 is a diagram of the electrical arrangement for operating the plunger-s of the reading board,

Figure 9 is a detail view illustrating the position of the raised dot spelling the word Braille in the alphabet yof that name,

b igure 10 is a view o f the code of perforations adapted for translating the letters of the Braille alphabet by use oflthe foregoing`v persons,but it -is anticipated that the prin-- ciples may apply in any case where sound, light or moving objects,`singly or in combination may be used to carry an idea by touch, eye or sound.

In applying the system to4 reading by the Figure 7 is a detail perspective View of the blind or near-blind, advantage is taken of the knowledge which blind people have of the present system of Braille reading by means of which raised dots indicate to the touch of the blind by their position on the l paper the letters which go to make up a word. The American revised Braille alpha- .bet consists of six dots in vertical and oblong formation, two vertical rows of threedots each constituting the imaginary oblong.

Figure 8 is intended to illustrate thekpovsition of the raised dots When the word `the first row, the letter I the dots'2 and 4 7e in the first and second rows, the letter L dots 1, 2 and 3 in the first rows, and the letter E the dots 1 and 5 in the first and second rows. Dot 6 does not appear in the Word but according to the Braille alphabet 75 occurs first in the letter IW-which consists of dots l and 3 in the first row and of dot 6 in the second row.

The machine in Figures 1 to 8 inclusive provides lfor communicating the Braille algo phabet by touch other than the feeling of the raised dots in Figure 9. Reduced to its essentials the machine comprises a frame 7 having' a projection Sat the front, herein known as the reading plate. Thereading g5 plate has holes 9 arranged in two vertical rows of three holes each, corresponding with the positions of the dots in the foregoing imaginary oblong of the Braille system. Ope'rablein these holes are the plungers 10, 11, 90 12, 13, 14:, 15 of as many electro-magnets suitably mounted beneath the reading plate.y

All of the electro-magnets are alike, and the description of the first oney will suice. In Figure 4 the plunger 10 slides in the brass 95 or other non-magnetic sleeve 16 situated within the tubular core 17 of the electromagnet 18. The core is of. magnetic material, and uponenergization of the electromagnet the armature 19 of the plunger 10 will be attracted, causing raising of the plunger in the hole 9 and projection of the button or cap of the plunger above the surface of the reading plate. The sleeve 16v projects slightly below the core 17, stopping the armature 19 and prevent-ing sticking thereof to the magnetic core 17. The button '20 is larger than the plunger 10 and particular plunger may be identified more readily.

A carriage 21 rides upon suitable bearings 22 on the frame 7. It is pulled to the left by the tape or ribbon 26 of a spring drum 24, which tape has connection with the carriage in the manner of known typewriter construction. The carriage progresses step by step to the left by the action of escapement mechanism (also shown in typewriter constructions) consisting of aratchet 25 (Fig. 6) a pawl 26, a rocker 27 which carries the pawl and space bar mechanism.

The latter comprises a rocker element 28 (Figs. l, 2 and 7) bell crank 29, connections 30 between the bell-cranks and the rocker element 28, and spaced bars 31 and 32 respectively situated at the left and right side of the reading plate 8. The operator may depress one or the other of the space bars 31 and 32 by one` or more otherwise idle fingers of the hand or hands upon the reading plate, the successive depressions ofthe space bars permitting the carriage 21 to move step by step across the frame so that the various letter-perforations of the-code (Fig. 10) may successively pass a predetermined point for the purpose of causing operation of the reading plate plungers. This intermittentor step by step movement causing intermittent opu eration of the reading plungers permits the operator to increase or decrease the intervals -between successive operations of the reading plungers in proportion to his or her ability to read the code of' characters and makes the ,machine adaptable to the ability or reading v speed of the different operators using it.

Mounted upon the carriage 21 is a platen 33, in this instance in the shape of a roller. The platen may be made of metal but preferably is provided with a metal covering 34. This covering forms part of an electrical circuit, the platen being introduced in such circuit b means of a brush or other contacter y35 (Figs. 3 and 8) `and a fixed set of spring so mounted upon the carriage 21 in reference to the platen 33 that a paper or other sheet 45 maybe inserted in the space between the two. The paper is fed forwardly by turning the platen 33 either by means of the knobs 46 at each end (Fig. 3), or by means of the more or less familiar ratchet and pawlmechanism 47 and 48 in Figure 5. Thev pawl is carried by a rocking arm 49 which has such connection with the lever 50`-\,(Fig. 3) that when the latter is pressed upon from the left it not only returns the carriage 21 to the starting position but also turns the platen 33 and feeds the paper 45 one line forwardly or upwardly. The throw of the pawl 48 must be arranged to produce sufficient turning of the platen 43 to accomplish the purpose, but inasmuch as the manner of doing this is shown in typewriter constructions the details are not necessari-ly entered into here.

A roller 49 has the paper 45 wound there\ on. The ends 50 of the roller are journaled in suitable bearings or brackets 51 forming part of the carriage 21. `The paper is fed under a presser or idler roller 52 and the end is deposited in a basket or other suitable receptacle 53, also mounted upon the carriage, in which basket the paper may be folded over from time to time as'it is unwound from the roller 49.

The sheet 45 will` be perforated to agree with the code in Figure 10 to therebyl form the letters of the word intended to be read through the mnse of touch upon the fingerboard' 8. The perforations (Fig. 10) extend in the vertical direction and occupy one or more positions in thesix numbered rows, the numberingof the. rows from 1 to 6 corresponding with the foregoing numbering of the dots in Figure 9. v

In Figure 8 the first perforation 54 extends over two-sixths of the alloted'vrtical distance (Fig. 10) and represents the letter B.

The next perforations 55 and 56 occupy thev a wire 59. The other pole of the battery is connected by means of a wire 60 with one side of each of the six electro-magnets 18 beneath the reading board. A switch 61 is interposed in the wire 60 so that the current may be cut ofi:l when the apparatus is not in use. Wires 62, 63, 64, 65, 66 and 67 connect the remaining sides of the various electro-magnets with the various spring contacts 36, 37, etc. Passage of the vpaper 45 beneath the stationary spring contacts mentioned will permit the ends of -the contacts to engage the metallic platen according to the extent of the various perforations so that one or more electrical circuits are closed through the various electro-magnets, causing raising of one or more of the plungers 10, 11,(etc. in agreement with the number and position of the dots of the Braille letters. I

Figure 11 illustrates a modification for use of the near-blind. The various plungers 10, 11, etc. are now substituted by lamps 68,69, 70, 71, 72 and 73 which, according to the disclosure are electric, and in practice may have variously colored bulbs so that the various ones of the six positions of dots may be identified more easily. In order to take the position of the reading board, the six lamps may be framed by a suitable number of clear or frosted lamps 74 giving a white light and producing a white border around the signal lamps.

The border lights 74 are connected in parallel,and are supplied with current from the battery 58 by wires 75 and 76, the former having a switch 77 by which the border may be lighted or extinguished as may be desired.

Otherwise the wiring is identical with that shown .in Figure 8, corresponding numerals being employed without further description.

Figure 12 illustrates a further modification adapting the principles of the invention to blind or nearly blind `and also to partially deaf persons, the signals consisting of three bells 78, 79 and 80, preferably of the singlestroke kind. These bells are so varied in pitch or tone that the ear can readily distinguish all three if'sounded at once, the bell 78 being highest in pitch, the bell 79 intermediate and the bell 80 lowest.

Only three spring contacts 81, 82 and 83 are necessary to the circuit arrangement of the bells. The battery 84 has-common connection at one pole with one side of each ofthe three bells by means of a wire 85. The remaining sides of the bells are connected with t-he three contacts mentioned by means of wires 86, 87 and 88. The cont-actor 89 which engagesthe metallic platen 90 has connection with the remaining pole of the battery through a wire 91. The ear cannot readily distinguish more than three independent sounds at one time and it is therefore necessary to modify the code in Figure 13 so that those letters of the Braille alphabet lwhich have more than three dots may be divided `.so that the dots in the second vertical row `letter R comprises dots 1, 2 and 3 in the rst row and the dot 5 in the second row. This letter is therefore formed in the sheet 45 (Fig. 12) by making a long perforation 92 involving all three of the bells, and a single perforation 93 involving only the central bell (Fig. 9). The letter Ik involves the dot 2 in the first row and dot 4 in the second row (Fig. 9), the sheet 45 therefore being perforated at 93 (Fig. 12) to involve a central bell 79 and 4at 95 to involve the first bell 78. The letter E is represented by perforations 96 and 97 which will permit ringing of first the bell 78 then the bell 79 representing dots 1 and 5 (Fig. 9).

By osettiug the pcrforations as described, it is possible to make the one set of three bells do double duty, or take the place of the second row of plungers in Figure 8 or second row of lamps in Figure 11. The time elapsfing between successive ringing of the bells and represented by the passage of the contact fingers 81-83 from one perforation Ias 92 to its complemental perforation 93, as the platen is moving, will indicate' the first and second rows and the longer interval between successive hand-controlled step by step spacing or feed of successive letter areas, will separate the letters and prevent confusion.

The bell 78 corresponds with dots 1 and 4 of Y the alphabet, the bell 79 with dots 2 and 5, and the bell with dots 3 and 6. v

The operation may be readily understood. The touch system, for totally blind persons is considered first. The sheet45 is previously 'i perforated to form letters and characters of the Braille alphabet, and is inserted in the' translating machine between the platen 33 and'rubber roller 44. The sheet may be as long as desired, and if sufficiently long will y be wound upon a roller 49 to be mounted upon the carriage 41, from which roller the sheet is Vunwound from time to time and deposited in a suitable receptacle 53.

A set of six stationary spring contacts 36, 37, 38. 39, 40 and 41 occupy a position corresponding with the usual printing point of the typewriter. The platen 33 passes the contact point with a step by step motion upon operation of the space bar mechanism which consists mainly of the space bars 31 and 32,v the pawl 26 and ratchet 29. The reader places his hands upon the reading board 8 in such manner that desired fingers take position upon the plungers, 1 0, 11, etc. certain remaining and idle fingers being used to Ydepress one or the other ofthe space bars 31 and 32 after each character has been read.

Assume the first perforation 54 as having reached the contact position or point. The springs 36 and 37 engage the metal covering 34 of the platen whereupon current flows from onepole of the battery 58', over wire 59, contact bar 35, covering 34, contact 36 and 37, wires 62 and 63,'the first two electro-magnets 18, and wire 60 to the other pole of the battery. The energization of the two electromagnets v auses raising of the plun'gers 10 and 11, producing two impulses agreeing with dots `1 and 2 in the letter B of the Braille alphabet (Fig. 9).

A depression of one or the other of the two spacing bars 31 and 32 will permit the carriage 21 to move sufficiently far to the left to bring the perforations 55 and 56 ofthe next nets and lamps as proposed.

character to the contact point. The circuits involving the electro-'magnets of the plungers 10, 11, 12 and 14 are readily traced without descri tion, the resulting `impulses agreeingr with ots 1, 2,3 and `5 orming the letter R of the Braille alphabet. The'modiication in Figure 11 uses six electric lamps 68,

69, etc., preferably variously colored, in substitution for the foregoing six plungers. The same style of perforations is intended to be used and, if desired, the lamps of Figure 11 and the electro-magnets 18 of the first form may be connected in parallel so that the touchand sight systemmay be used in combination. It is deemed unnecessary to illustrate this combination because it is within the province of any electrician to combine the electro-inag- 'l`he operation will be the same excepting of course that lamps will become lighted in place of plungers being raised, butin the case o1' the combination both lamps will be lighted and plungers will be raised simultaneously.

The modification in Figures 12 and 13 makes use of three bells which are successive- 1y lower in pitch, the code in Figure 13 havsir ing offset perforated components to suit those letters of the Braille alphabet which employdots in the second vertical row of the imaginary outline. This arrangement4 will produce impulses of one or more of the three bells at short intervals, one illustration being sutlicient to remindY the reader of the operatlon which is set forth earlier in the description.

-Take the letter R": The perforation 92' the second dot 5 in the second vertical row.

It is regarded as within the province of the invention to employ instruments other than bells, such instruments being capable of opel-- ation by electro-magnetic means. But bells offer the most practical means, both because of their loudness andV availability. If desired, a number of reading plates, sets of bells or frames of lights may be introduced into the circuits to operate in different parts of a room, in different rooms or anywhere where -it is desired to have them, it being proposed to operate all such devices from some central point;

While the construction and arrangement of th'e improved signaling system is that ot a generally preferred form, obviously modifications and chan es may be made Without departing from tie spirit of the invention or the scope of the claims. 75

1. Apparatus ofthe character descibed comprising a metallic platen having ap licable thereto a sheet provided with para lel lines 'of perforations corresponding to a code 80 of communication, a plurality of signaling devices by which the code is translated, a source of ener y having one terminal connected with said platen and the other ter- 4minal connected with one side of each of said 85 devices, a plurality of contacts fixed in position relatively to the platen respectively connected with the remaining sides of said devices and being in position to engage the platen through successive portions of a line of perforations in said sheet, manually operable means for electing movement of the platen in one direction in respect tosaid contacts permitting successive engagement thereof with the platen through and according to the extent of the perforations in successive portions of the line of perforations to render vlcorresponding signaling devices operative,

and means for moving the platen in another` direction to bring succeeding parallel lines of perforations in position or passage beneath the contacts. A v

2. Apparatus of the character described comprising a plurality .of electrical signaling devices arranged 1n agreement with the 105 position of the com onents of a code of communication, a meta lic platen having a plicable thereto 'a sheet provided with mes--l ofperforations which perforations are varied in extent, a plurality of 'contacts respec- Il.

' tively connected 4with one side of said devices fixed relatively to and engageable wthithe platen throughperforations in said sheet,A manually operable means to advance theJ platen past said cont-acts with a step by step .115-

lnotion 4permitting various contacts to engage the platen accordlng to the extent of the perforations in successive portions of'4 a line of perforations brought thereunder, and a source of current having one terminal con- 12o nected with the laten and another terminal connected with tlie other side of said devices, energizing such number of the devices as agrees with the number of contactspermitted to engage the platen through th`e perforations. v l

3. Apparatus of the character described comprislng a reading boardhaving a plurality of holes arranged in a reement with the Braille code, a plurality o electro-magnetic means each having elements movable in said holes, a metallic platen having applicable thereto a sheet containing a line of perforations of suitable extent and formation to involve determined components of said code, contacts equal in number to said devices being respectively connected With one side of the devices, manually operable means for effecting step by step movement of the platen past said contacts permitting one or more to engage the platen through and according to the position and extent of the perforations in successive portions of the line of perforations moved thereunder, and a source of energy having one terminal connected with the platen and the /other terminal with the remaining sides of said devices, energizing the electro-magnetic means of the engaging contacts to move the respective plungers in the holles and thus reproduce components of said coc e.

4. Apparatus of the character described comprising a reading board having' a plurality of holes arranged in agreement with the Braille code, electro-magnets having plungers extending into the holes, the ends normally being Hush with one surface of the reading plate, a metallic platen to which is applicable a sheet having a line of perforations of an extent and location to involve components in the characters of said code, a plurality of contacts respectively connected With one side of said electro-magnets, manually operable means for effecting step by step movement of the platen past said contacts so that various ones engage the platenL according to the extent and location of the perforations in successive portions of the line of perforations, and a source of energy connected with the platen and with the remaining side of said electro-magnets causing e-nergization of the electro-magnet agreeing with said engaging contacts to project corresponding plungers .above the surface of the reading board thereby reproducing the selected com` ponents of the Braille codel 5. Apparatus of the character described comprising a frame, aI projecting portion on the frame having a plurality of holes constituting a reading board, electro-magnetic means mounted upon the reading board havingplungers projecting into the holes and being Hush with one surface of the reading board, the arrangement of the holes and plungers agreeing with the positions of the character-components of the Braille code, a carriage mounted upon the frame, a metallic platen and a rubber roller mounted upon the carriage receiving therebetween a sheet having a line of perforations of an extent and position to involve desired components of said code, a plurality of contacts iixed upon the carriage and respectively being connected with one side of the electro-magnetic means, means including a manually operable spacing bar situated b side the reading board for moving the cariage, .platen and line of perorations on said sheet step by step past said contacts permitting engagement of certain contacts with the platen according to said extent and position of the vperlorations, and a source of energy \connected with the platen and to the remaining side of said electromagnetic means fo-r completing electrical circuits to project certain plungers above the surface of the, reading board thereby to reproduce the characters of said code.

6. Apparatus of the .character described comprising aplurality of electrical signaling devices, a metallic platen, a source of electrical current having one terminal connected with the platen and the other terminal conneeted with one side of said devices, a sheet applied to the platen having a line of perfo- 'rations therein corresponding to a code of communication, a series of contacts connected with the other side of said devicesand engaging the platen as permitted byand according to the extent of the perfora-tions to close electrical circuits through a corresponding number of said devices, and manually operable means for effecting intermittent and relative movement of said platen and series of contacts-to bring successive portions of a line of perforation's and said contacts into positions of cooperation.

7 Apparatus of the character described comprising a metallic platen, a sheet applied to the platen having perforations exposing portions of the platen beneath the sheet, electrical signaling devices, a. source ofn current having one terminal connected with the platen and the other terminal connected with one side of said devices, contacting means each having connection with the other side of v the respective devices and fixed in position relatively to the platen, and manually operable means for effecting intermittent movement of the platen past said contact means permitting engagement of the contact means ywith the platen through successive portions of a line of perforations to render the signaling devices operative.

JENS K. GRONDAHL. 

